In various types of hybrid and electric powertrain configurations having an electric motor/generator coupled to an automatic step-ratio transmission, the motor may be stopped when the transmission is in Park or Neutral to conserve energy. When the motor is stopped, the torque converter impeller and the transmission main oil pump, which are driven by the motor, also stop. When the driver moves the gear selector from Park or Neutral to Drive or Reverse, one or more clutches are engaged to place the transmission in an appropriate forward or reverse gear to provide torque to the vehicle wheels and propel the vehicle. However, without the transmission main oil pump operating, the line pressure provided by any auxiliary oil pump may not be sufficient to quickly engage the shifting clutches. As a result, the wheel torque delivery may be delayed. Any significant delay may be particularly problematic if the driver moves the gear selector into Drive or Reverse while simultaneously pressing on the accelerator pedal.